Vac issue

[TYHOGG]

Having a problem here and running out of ideas.

At start up the truck will pull 15in.hg of vac no problem. I drive it 20 ft. and when the rpm's come back down the vac will slowly rise towards 0 and hover a little then the truck wants to die.

I have tripled check all my vac fittings and everyone is attached, sealed and zip tied. Would a bad pcv valve cause this probelm? On the throttle body i have the top port capped off, the middle port is connected to pcv, and the bottom port is open. Can anyone think of something i might have missed. It is the last issue i have, otherwise the truck is running like a raped ape.

Thanks,
Adam

 

[Quickstop [UK]]

Re: Vac issue

if you keep the rpm up does the vac stay there?

 

[TYHOGG]

Re: Vac issue

if you keep the rpm up does the vac stay there?

Yes with a little throttle applied the vac will stay around 10/12in.hg and the truck will continue to run. It seems to be only and idle issue. I'm gonna try data master today and see if i notice anything out the ordinary.

 

[SIMPLE]

Re: Vac issue

Did you get this figured out? I've having the same issue. Will a bad EGR cause this also?

 

[TYHOGG]

Re: Vac issue

i replaced the pvc with a gm one at it idles good now. you should be able to unplug the egr and see if it changes.

 

[SIMPLE]

Re: Vac issue

Okay I'll try that. Seems the only place to get the PCV is at the stealer?

 

[SIMPLE]

Re: Vac issue

Swapped the PCV and it help a good bit, still runs a little rough though. I'll do a proper tune and see it that helps. What's people's opinion on the MSD stuff(distributor, coil, and the 6A box)? Worth the $$$?

 

[Try Me]

Re: Vac issue

Swapped the PCV and it help a good bit, still runs a little rough though. I'll do a proper tune and see it that helps. What's people's opinion on the MSD stuff(distributor, coil, and the 6A box)? Worth the $$$?

I had the msd dist and coil and they never gave me trouble. Stay away from the 6 box though, left me sitting and i know im not the only one. I had to bypass mine in a parking lot to get the truck home. I later bought an Accel 300+ kit that was box, coil, and plug in harness for our trucks and it made a much bigger improvement than the MSD 6 box. Plus if i recall correctly its cheaper.

 

[SIMPLE]

Re: Vac issue

Good to know, thanks!

 

[El_Jeffe]

Re: Vac issue

i replaced the pvc with a gm one at it idles good now. you should be able to unplug the egr and see if it changes.

Whats up Adam? Glad you got the idle fixed. I probably have to change mine to. It also idles kind rough. BTW, When are you driving your truck over to my place so I can check it out? The long drive will help you break in the new motor & parts. Later

Rey F.

 

[TYHOGG]

Re: Vac issue

Whats up Adam? Glad you got the idle fixed. I probably have to change mine to. It also idles kind rough. BTW, When are you driving your truck over to my place so I can check it out? The long drive will help you break in the new motor & parts. Later

Rey F.

Man it would be a seriously long drive now, a little over 1200miles. lol.